Processes for breaking petroleum emulsions



Patented Aug. 11, 1936 UNITED STATES PATENT OFFICE Melvin De Groote, St. Louis,

Mo., assignor to Tretolite Company, Webster Groves, Mo., a corporation of Missouri No Drawing. Application December 21, 1935, Serial No. 55,615

4 Claims.

This invention relates to the treatment of emulsions of mineral oil and water, such as petroleum emulsions, for the purpose of separating the oilfrom the water.

5 Petroleum emulsions are of the water-in-oil type, and comprise fine droplets of naturally-occurring waters or brines, dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion.

L They are obtained from producing wells and from the bottom of oil storage tanks, and are commonly referred to as "cut 0 roily oil, emulsified oil and fbottom settlings".

The object of my invention is to provide a novel and inexpensive process for separating emulsions of the character referred to into their component parts of oil and water or brine.

Briefly described, my process consists in subjecting a petroleum emulsion of the water-in-oil type to the action of a treating agent or demulsifying agent of the kind hereinafter described, thereby causing the emulsion to break down and separate into its component parts of oil and water or brine, when the emulsion is permitted to re- 5 main in a quiescent state after treatment, or is subjected to other equivalent separatory procedures.

The treating agent or demulsifying agent used in my process consists of a chemical compound 0 characterized by the presence of both an oxyhendecenoic acid residue and a keto fatty acid residue derived from castor oil, in the same molecule.

In U. S. Letters Patent to Melvin De Groote and 5 Bernhard Keiser, No. 2,023,996, dated December 10, 1935, there is described a process for breaking petroleum emulsions by means of oxyhendecenoic acid materials. As stated in said patent, hendecenoic acid is an unsaturated acid 0 similar to certain fatty acids, but apparently not occurring naturally in any fat or oil. It is a lower homologue of oleic acid, and is obtained by distilling ricinoleic acid or the glyceride thereof (castor oil) under diminished or atmospheric 5 pressure. It is sometimes known as undecylenic acid. Its formation from ricinoleic acid, for example, is indicated by the following reaction:

3 In preparing the treating agent or demulsifying agent employed in the present process, it is not necessary that the hendecenoic acid, which is employed as a .raw material, be absolutely pure,

; but it may be .of a' technical quality, so as to contain some unconverted castor oil and certain products of decomposition other than hendecenoic acid. It may contain some oenanthol (heptoic aldehyde). This aldehyde can be removed by blowing an inert gas through the commercial hendecenoic acid at a relatively low temperature. 5

Oxy-hendecenoic acid bodies are derived from hendecenoic acid of technical purity in various manners, such as those outlined in the aforementioned De Groote and Keiser patent. One method employed isto form the fatty sulfates with subsequent hydrolysis. Another method is dependent upon oxidation or hydroxylation under certain controlled conditions. For example, hendecenoic acid of technical purity may-be subjected to oxidation by any of the methods conventionally employed for oxidation of castor oil and the like. My preference is to oxidize hendecenoic acid at relatively low temperature by means of moist air under pressure. I prefer to use a temperature of 125 to 135 C. to use approximately 45 to 75 lbs. gauge pressure. If desired, hendecenoic acid may be oxidized at a higher temperature by means of air or oxygen at atmospheric pressure.

I have referred to the product obtained by oxidizing hendecenoic acid as "oxy-hendecenoic acid. The expression oxy-hendecenoic acid" is intended to refer to the derivatives in which additional oxygen has been introduced into the molecule. Forinstance, this may be in the manner indicated by the formular CnHroOa. This represents the saturation of the ethylene linkage by means of an atom of oxygen. It is believed that oxidation, especially with moist air, results in the conversion of this added oxygen atom into two hydroxyl radicals, so that ultimately one apparently obtains dihydroiw-hendecatoic acid, as indicated by the formula C11H2o(OH) 202. In other words, the addition product of hendecenoic acid is the substitution product, at least hypothetically, of hendecatoic acid.

As further stated in said De Groote and Keiser Patent No. 2,023,996, it is immaterial whether there be introduced an oxygen atom or two hydroxyl radicals in the hendecenoic acid body to produce the oxy-hendecenoic acid body. It is obvious, of course, where a hydroxyl is formed, that one has a hydroxylated fatty acid or hydroxylated fatty acid compound, and that the fatty acid at least may act either as an alcohol or as an acid in the same sense that ricinoleic acid, for example. may act as an alcohol or acid.

In the co-pending application for United States Letters Patent, of Melvin De Groote, Bernhard Keiser and Arthur F. Wirtel, Serial No. 760,033, filed December 31, 1934, there is described a process for breaking petroleum emulsions by means of unpolymerized keto fatty acid bodies or materials.

It is well known that fatty acids or fatty bodies can be subjected to chemical treatment so as to yield keto fatty acids, that is, fatty acids in which a ketonic group (a carbonyl group) is present. One example is the conversion of ricinoleic acid into ketohydroxystearic acid. (See Lewkowitsch Chemical Technology of Oils, Fats and Waxes,

6th edition, volume 1, page 242.) In a general way, the manufacture of such ketonic acids is dependent upon the treatment of an unsaturated fatty body or fatty acid, such as ricinoleic acid, oleic acid, or the like, with a halogen, such as bromine, so as to form a halogen addition product, for example, ricinoleic-acid dibromide, which is then converted into ricinstearolic acid. Ricinstearolic acid, on treatment with sulfuric acid, yields ketohydroxystearic acid.

In a second co-pending application for patent of said Melvin De Groote, Bernhard Keiser and Arthur F. Wirtel, Serial No. 760,032, filed December 31, 1934, there is disclosed the use .of polyketo fatty acid bodies for the purpose of breaking petroleum emulsions. Polyketo fatty acids may be derived by polymerization of keto fatty acids which have been previously derived in the manner described by Lewkowitsch, mentioned above.

In the present application, the expression "keto fatty acids or keto fatty acid bodies is intended to include both unpolymerized keto fatty acid bodies and polymerized (polyketo) fatty acid bodies. It is more economical, in many instances, to prepare the reagent or demulsifying agent employed in my present process, from a polyketo fatty acid body than from an unpolymerized one. The reason for this is that it is more economical to produce polyketo fatty acid bodies than unpolymerized keto fatty acid bodies.

In the production of polyketo fatty acids or their salts or esters, by pressure oxidation at relatively low temperatures, one may employ any suitable unsaturated,hydroxylated fattymaterial, such as castor oil, ricinoleic acid, diricinoleic acid, or other material of the kind described in the aforementioned De Groote and Keiser Patent No. 2,023,996, or any other suitable material. In a third co-pending application of Melvin De Groote, Bernhard Kaiser and Arthur F. Wirtel, Serial No. 160,031, filed December 31, 1934, there is described a novel" methodfor producing a new composition of matter, consisting of polyketo fatty acids and their salts and esters, said method contemplating pressure oxidation at relatively low temperatures, such as 135 C. or less, and the product resulting from said method consisting of materials high in polyketo fatty acids, which have the same characteristics as polyketo fatty acids derived by esterifying or condensing a keto fatty acid, such as ketohydroxystearic fatty acid with ricinoleic acid or diricinoleic acid or oleic acid or tricinolein.

Briefly described, the method described in said pending application Serial No. 760,031 for producing such polyketo fatty acids by pressure oxidation, consists in mixing an unsaturated, hydroxylated, fatty body of the kind previously described, such as castor oil, with not over 10% of a true drying oil, such as linseed oil, or perilla oil, or the acids thereof, and subjecting the same to pressure oxidation at approximately 15 to 7.5 lbs. gauge pressure by means of ordinary moist air and at a temperature of not over 135 0., and preferably, at about 120 C., for approximately 10 to 30 hours. A small amount of a fat splitting sulfonic acid, such as approximately of Petroif reagent (oil-soluble petroleum sulfonic acids) may be present during oxidation.

It is well known, of course, that castor oil is an alcohol, and in fact, a secondary alcohol. It is furthermore well known that ketonic acids are produced by the cautious oxidation of hydroxy acids containing the secondary alcoholic group, as, for example, oxidation of lactic acid to pyroracemic acid. In said reaction the CH (OH) group is converted into a C0 group. The cautious oxidation of castor oil or ricinoleic acid conducted under the previously specified conditions results in the formation of a ketonic acid, which may be indicated by the following formula:

However, oxidation not only takes place at the hydroxyl position, but also at the ethylene linkage, with probably the absorption of oxygen and then conversion into hydroxyl groups, and thus the ketonic acid produced may represent a saturated, dihydrcxy acid which may be indicated by the following formulas:

on on However, it is well known that oxidation reactions tend to polymerize or form ester acids, ethers, etc., and thus the resultant product represents ketonic acids in the polymerized form, 1. e., derived from two or more molecules, at least one of which must contain a ketonic group. Obviously, such ketonic fatty acids may be of the hydroxy type as well.

The formation of ketohydroxystearic acid in the usual manner (see Lewkowitsch, .Chemical Technology of Oils, Fats and Waxes, 6th edition, volume 1, page 242) with subsequent reaction with ricinoleic acid, diricinoleic acid, oleic acid, tricinolein, etc., results in a compound representing substantially nothing other than polyketo acids. On the other hand, I am aware that the products obtained by pressure oxidation in the manner referred to previously, may result in products containing a significant amount or majority of polyketo acids, but may contain certain other nonketonic material of the kind present in various conventional or special blown oils. Since such non-ketonic materials are also effective quite frequently for the treatment of oil field emulsions, I prefer to use the impure form of polyketo acids or their salts or esters, as obtained by pressure oxidation, in producing the demulsifying agent employed in my present process. This is purely a matter of economy. The pure forms, relatively free from extraneous materials, may be employed.

I am fully aware that migration may take place in a fatty molecule. For instance, that the formation of stearolactone from hydroxystearic acid appears to depend on the migration of the alcoholiform hydroxyl. I am also aware that in the case of the common non-fatty ketonic acid, aceto-acetic acid,that certain reactions are known to take place which suggest that aceto-acetic acid may, as far as those reactions are cdhcemed, react more as an aldehyde or as an aldehydic acid than as a ketonic acid. Such wandering of a hydrogen atom and change in position of a double bond is referred to as keto-enolic tautomerism (Bemthsen, Textbook of Organic Chemistry", 2nd edition, 1931, page 231). I believe that this or a comparable change may take place in these polyketonic acids or bodies previously described, and possibly in regard to some reactions, these polyketo acids or esters thereof act more as if they were aldehydic acids or esters or salts thereof. In other words, if these polyketonic acid bodies are to be used in a mixture where aldehydic acids would be incompatible, it is also likely that these polyketonic acids or their esters may be incompatible, for the reason that they really may be aldehydic acid bodies. It is to be noted thatreagents of the kind employed for determining the presence of the carbonyl group in ketones also usually detect the presence of the carbonyl group in aldehydes. It is to be understood that in the claims where the products are characterized by the presence of ketonic radicals, that such acids might ultimately prove to be aldehydic acids, or at least convertible under certain conditions of use, or else under certain conditions of identification, possibly they become converted into aldehydic acids, and it is not intended that the word ketonic or keto be interpreted as excluding the meaning of aldehydic in the sense previously described or discussed, i. e., that both have the carbonyl (CO) radical present, and their ultimate composition in carbon atoms, hydrogen atoms, and oxygen atoms is identical.

The present process, as differentiated from the processes of the previously mentioned co-pending applications for patent, which are also concerned with demulsification, is characterized by the fact that I employ a demulsifying agent of the kind in which there is present both an oxy-hendecenoic acid residue and a keto fatty acid residue in the same molecule. The keto fatty acid residue is characterized by the fact that it is obtained from castor oil. The formation of such materials, as employed in the present process, is relatively simple. Since the oiw-hendecenoic acid may be considered as an acid alcohol type of reagent in the same sense that ricinoleic acid is an acid alcohol, one may obtain the same reaction from a molecule of oxy-hendecenoic acid and a molecule of keto fatty acid as one would obtain from two molecules of ricinoleic acid combining to form monobasic diricinoleic acid. Likewise, any other alcohol acid type of material such as ricinoleic acid, hydroxystearic acid, or the condensation product of ethylene glycol with phthalic acid or with oxalic acid, or with maleic acid, may serve as a bridge or a connecting link by combination with a molecule of oxy-hendecenoic acid and a molecule of keto fatty acid. Such material, when used as a connecting link or bridge, must be amphoteric, if it can be employed to combine with a hydroxyl of an oxy acid and the carboxyl of a keto fatty acid. The keto fatty acid may be of the hydroxy type, and act as an alcohol. Dehydration of two hydroxyl radicals, one from oxy keto acid or its salt or ester, and the other from oxy-hendecenoic acid or its salt or ester, may result in an other type reaction.

Other means of combination are readily available, such as the formation of a glyceride in which a molecule of oxy-hendecenoic acid and a molecule of keto fatty acid are united with a molecule of glycerol. Likewise, two molecules ,of oxy-hendecenoic acid and one molecule of keto fatty acid or else two molecules of keto fatty acid and one molecule of oxy-hendecenoic acid may combine with one molecule of glycerol, to give a triglyceride. One molecule of oxy-hendecenoic acid and one molecule of keto fatty acid may be united by means of ethylene glycol or some other similar glycol.

If the oxy acid, that is, oxy-hendecenoic acid, is acting by virtue of its alcoholic hydroxyl, one

need not employ the acid itself, but one may employ any suitable salt, such as a sodium salt, ammonium salt, potassium salt, or amine salt, such as the triethanolamine salt. Where the oxy acid is acting by vitrue of its carboxylic hydrogen, one need not use the acid itself, but one may employ a combination wherein the alcoholic hydroxyl has already been combined with some other acid, such as ricinoleic. All these reactions are essentially esterification reactions. As such, they are best promoted at a fairly high temperature, and preferably slightly above the boiling point of water. The passing of dry hydrochloricacid gas hastens the reaction.

It may be possible to conduct the oxidation of castor oil (or ricinoleic acid, or polyricinoleic acid derivedfrom castor oil) and the oxidation of hendecenoic acid simultaneously so that oxyhendecenoic acid or oxy-hendecenoic acid bodies and poly keto fatty acids or poly keto fatty acid bodies are produced simultaneously and react further, so as to produce a molecule which is characterized by the presence of both an oxyhendecenoic acid residue and a keto fatty acid residue. Such procedure may prove the most valuable means of producing the reagent employed in the present process of breaking petroleum emulsions.

The reagent or demulsifying agent used in my process is preferably obtained or produced by heating a molecular weight of poly keto fatty acids derived by the oxidation of ricinoleic acid, with a molecular weight of oxy-hendecenoic acid glyceride derived by the oxidation of hendecenoic acid glyceride, obtained by the pyrolysis of castor oil. Such materials may be heated together, and when so treated, produce a very valuable demulsifying agent for breaking crude oil emulsions.

If desired, any free acidity which is present in the preferred reagent may be neutralized by triethanolamine or by any other suitable amine, such as monoamylamine, benzylamine, etc. The free acidic carboxyl may be converted into a salt, such as a sodium, potassium, or ammonium salt. The free acidic carboxyl, of course, may be combined with an alcohol such as ethyl, methyl, or propyl alcohol, or with glycerine.

Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water; petroleum hydrocarbons, such as gasoline, kerosene, stove oil; a coal tar product, such as benzene, toluene, xylene, tar acid oil, cresol, anthracene oil, etc. Alcohols, particularly aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc. may be employed as diluents. Miscellaneous solvents, such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc. may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of my process may be admixed with one or more of the solvents customarfly used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable well known classes of demulsifying agents, such as demulsifying agents of the modified fatty acid type, the petroleum sulfonate type, the alkylated sulfo-aromatic type, etc.

It is well known that conventional demulsifying agents may be used in a water-soluble form,

both oil and water solubility.- Sometimes they may be used in a form which exhibits relatively true-in regard to the material or materials employed as the demulsifying agent oi my process.

In practising my process a treating agent or demulsifying agent of thekind above described is brought into contact with or caused to act upon the emulsion tobe treated, in any of the various ways iorby any of the various apparatus now generaliy used to resolve or break petroleiini emulsionswith a chemical reagent.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A process'ior breaking petroleum emulsions oi the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsifying agent comprising a chemical compound characterized by the presence of both an oxy-hendecenoic acid residue and a keto fatty acid or in an oil-soluble form, or in a form exhibiting residue derived from castor oil in the same molecule.

2. A process for breaking petroleum emulsions of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsity ng agent comprising a chemical compound in the to of a salt, characterized by the presence of bo h an oxy-hendecenoic acid residue and a keto fatty acid residue derived from castor oil in the same molecule.

3. A process for breaking petroleum emulsions of the water-in-oil type, which consists in subjecting the emulsion to the action of a demulsitying agent comprising a chemical compound in the form of an acid,-characterized by the presence of both an oxy-hendecenoic acid residue and a keto fatty acid residue derived from castor oil in the same molecule.

. 4. A process for breaking petroleum emulsions of the water-in-oil type. which consists in subjecting the emulsion to the action of a demulmtying agent comprising a chemicalcompound in the form of an ester, characterized by the presence of both an oxy-hendecenoic acid residue 25 and a keto fatty acid residue derived from castor oil in the same molecule. I

' MELVIN DE GROOIE. 

